Device for emergency cutting off fastened seatbelts

ABSTRACT

The fastened seatbelts cutting device for transport vehicle, especially automotive vehicles, featuring bushing-shaped housing with an explosive charge or a gas generator inside, the charge and generator connected with a system activating the belt cutting drive, also featuring a cutting knife and a slot for this knife or blade and a slot to house the belt being cut, has a pusher ( 6 ) located between the gas generator ( 4 ), chamber ( 3 ), and the cutting segment ( 7 ), sealed with respect to the working chamber ( 8 ) in the guide chamber ( 5 ), and the blade ( 9 ) cutting edge ( 21 ) is one of the sides of triangle connected with the blade ( 9 ) body seated in the cutting segment ( 7 ).

The subject matter of this invention is the device for emergency cutting off fastened seatbelts in transport vehicles, especially automotive vehicles, the device having a tubular housing with an explosive charge or a gas generator installed inside, connected with a system activating the drive of belt cutting, furnished with a cutting knife and a gap for that knife or a blade and a gap for the seatbelt being cut to be placed in it,

After an accident in which means of transport are involved drivers and passengers have difficulty releasing from fastened seatbelts and leaving crashed vehicles, because of jammed seatbelt lock or not being able to have access to seatbelt lock, and because of after-accident shock, which especially refers to injured individuals, children the disabled and the elderly Fast leaving a vehicle by victims is very important as—after such an accident—there is a serious risk of fire of such a vehicle, the risk of being hit by other vehicles, or in a situation in which such a vehicle falls into water and sinks—there is a serious threat to health and risk of fatality for individuals trapped in such a vehicle. Rescuing of injured passengers and a driver after accidents is always difficult because of fastened seatbelts (not unfastened seatbelts).

The manner of emergency cutting off fastened seatbelts, known from Polish patent description P-366686, especially after an accident, fire or other occurrence which causes abrupt change of a vehicle position, consists in determining, by the control segments, the following facts occurred: seatbelts fastening status, accident occurrence, time elapsed from the accident occurrence, ceasing uncontrolled movement of vehicle, activating seatbelt tensioners or airbags, or starting fire, and then, transmission of these signals to a processor which, depending on the type of signal, causes automatic cutting off seatbelt straps by a moving blade powered with a pyrotechnic/explosive charge/load.

From a Polish description of the patent application of invention number 386089 the device for automating cutting off seatbelts is also known, the device whose body has a tubular element connected with its housing, and this element is furnished with an explosive charge located near its bottom and a moving cutting segment furnished with a blade, installed inside this element, while the device housing has a rectangular go-through gap for that blade, which—seen from its side—has the shape of a right-angled triangle or an obtuse-angled triangle. It is favourable when the cutting blade of the device has the shape of a rectangular strip or a rhombus, or a trapeze, or an arch-shaped element. In other embodiment of this device, the cutting segment is a pressing mandrel, fitted movably in the tubular body and fitted under it a movable blade of a cutter, connected by an articulated joint with one end of a fixed arm of the housing, and a longitudinal go-through gap is made in the housing arm opposite the cutter blade, and the bottom end of a cylindrical mandrel has a shape of a truncated cone and an explosive charge is fitted over the upper end of this mandrel.

A German patent description of a utility design number DE29809585U1 reveals also a device for cutting off a seatbelt, the device being made up of a two-part housing, one part of the two, attached to a transverse element of car body, is furnished with a fixed knife and the other part is furnished with a moving knife and an initiating set placed over it, driving the knife furnished with an initiator, and both parts, placed opposite each other, are furnished with rolls guiding the hip belt and the arm belt. After an airbag goes off, a delayed initiating impulse is given to the initiator and the latter initiates, in turn, the driving set, which causes the movement of the moving knife towards the fixed knife, and both seatbelts get cut off along the matching line of those two knives.

The patent description number W02006/109 106 A1 also reveals a device for quick releasing from fastened seatbelts, the device having a rectangular hollowed housing, furnished with an element attaching the flat section of a seatbelt and with a cutting element powered with an explosive element/device, having three controlling devices, and the cutting element has also a moving part with a blade directed towards the straight section of a seatbelt. The moving element having adequate inertial mass is situated in two guides attached to a support of the housing. Two out of three devices controlling the element which actuates the cutting element, are actuated by hand and the other inertial element is actuated automatically, and one of the hand-operated controlling devices co-works with the removable device blocking the movable blade element. An explosive, flexible actuating devices pushes (presses) the movable blade element towards the blocking element and shifts the movable element to its second position. Besides, an attaching element contains two locking elements positioned on both sides of the housing to keep a section of seatbelt straight, pressed between two walls of the housing and the fixing element, and the housing has also an oblong gap inside and side walls. The moving element with a blade slides along the mentioned guides limited with the side walls of the housing, and the movable blade shifts in the gap in the housing, powered by its moving element of appropriate inertial mass.

A French patent description, number 2382902, reveals a device for cutting off seatbelts, the device being made up of a cutting device, a device holding this cutting device in appropriate proximity to the belt being cut, a device storing energy necessary to cut this belt, a device sending a signal to activate the device storing energy, a sensing device connected with the energy storing device, the energy being adjusted to an abnormal situation, and the device being furnished with a pin pushing device located in an opening and a device (pusher) with a bent spring (tensioned) pushing the mentioned pin along this opening towards the energy storing device. The spring device in tensioned position is held by a readily fusible wire which gets broken in response to activation of the sensing device, signalling an abnormal situation occurring, and the same causing the spring release and, in turn, activating the movement of the pusher pin. The aforementioned energy storing device is furnished with a chemical drive in the form of a blank cartridge, while the cutting device is made up of a blade and an anvil device between which the seatbelt runs, and the cutting blade is fixed on a piston held in the opening of the holding device, and the sensing device, on starting an abnormal condition, connects a source of electric current with this readily fusible wire melting it, and as a result the blank cartridge explodes and the piston with the blade is pushed outside and cuts the safety belt.

The essential drawback of the seatbelt cutting design solutions known so far is the fact that the flame caused by the pressure and resulting hot gases from burnt explosive loads, noxious for people remaining in the after-accident motor vehicle which, in turn, poses a risk of fire inside the vehicle cabin. Besides, most of the known devices have too high own mass and sophisticated design, which requires specialized manufacture process engineering, which, in turn, considerably increases the production costs.

The objective of the invention is to eliminate totally the mentioned drawbacks and inconvenience found in the seatbelt cutting devices known so far.

The objective was attained in the solution as per the invention in which the fastened seatbelt cutting device in transport vehicles, especially automotive vehicles, has a pusher located between the gas generator chamber and the cutting segment, air-tight sealed relative to the working chamber, in the guiding chamber, and the mass of the cutting cylindrical mandrel in the cutting segment is adjusted to the rated power of gas generating explosive load. In another variety of the device, after the gas generator chamber, on the cutting segment, there is an elongated cylindrical mandrel, being an extension of this cutting segment towards the gas generating chamber, tight-sealed relative to the working chamber, in the guiding chamber. In both varieties of the device the cutting edge of the cutting blade is one of the sides of a triangle connected with the body of the cutting blade, embedded in the cutting segment.

The sealing consists of at least one gasket placed in the guiding chamber. The mass of the cylindrical cutting mandrel, in the cutting segment, co-working with the pusher, is adjusted to the rated power of gas generating explosive load. In the first variety of the cutting device, the first of the gaskets is mounted on the pusher which forms a separate part relative to the cutting segment, and the other gasket is placed in in the guiding chamber at its stop face. They prevent inadvertent move-out of the cutting segment towards the belt being cut. In the second variety of the cutting device the first gasket is fitted on the cylindrical mandrel of the cutting segment on its end part and moves along with it in the direction of work of the cutting segment, and the other gasket is placed in the guiding chamber at its stop face, preventing inadvertent move-out of the cutting segment towards the belt being cut, and, at the same time, it is necessary to have the length L of the cutting segment longer than the length L1 of the working chamber. In another variety of the cutting device, the gasket is put on the cylindrical mandrel of the cutting segment on its end part on the side of the gas generator and moves along with it in the direction of work of the cutting segment, and, at the same time, it is necessary to have the length L of the cutting segment longer than the length L1 of the working chamber.

The cutting edge of the cutting blade is one of the sides of a triangle connected with the body of the cutting blade, embedded in the cutting segment, and the top point of this edge is a point of the cutting blade closest to the belt being cut. In another variety of the device the cutting edge of the cutting blade is one of the sides of a triangle connected with the body of the cutting blade, embedded in the cutting segment and the top point of this edge is a point of the cutting blade closest to the gas generator.

The sealing of the pusher or of the pusher and the cutting segment totally prevents any risk of fire as well as emission of gases and smoke and/or flame, being the products of combustion in the gas generator, outside the device through the gaps for the belt and in the cutting segments, the products being noxious for people remaining in the damaged motor vehicle.

As per the invention, the application in the device of the system composed of the elements functionally linked with one another, installed in the tubular part of the device's body, including the pusher or the elongated cylindrical body between the gas generator and the seatbelt cutting segment, permitted to reduce and simplify substantially its configuration and develop a simple and compact configuration of the device.

An example of the device embodiment as per the invention is presented in drawings, including

FIG. 1—which shows the automatic seatbelt cutting device in exploded perspective view, with the short cutting element and the pusher;

FIG. 2—shows the same device in longitudinal section;

FIG. 3—shows the automatic seatbelt cutting device in exploded perspective view, with the movable long cutting element without a pusher;

FIG. 4—shows the same device in longitudinal section;

FIG. 5—shows its cross section A-A from FIG. 4.

FIG. 6—shows the side view of the cutting segment with the top of the cutting edge protruded towards the belt being cut; and

FIG. 7—shows the side view of the cutting segment with the top of the cutting edge withdrawn towards the gas generator, and the embodiment is described below.

The device for automatic cutting off fastened seatbelts in transport vehicles, as per the invention, is made up of a tubular housing 1 having a go-through opening 2 made up of three chambers, the first of which in the gas generator 4 chamber 3 the second chamber 5 is a chamber guiding the cylindrical mandrel 7 a of the cutting segment 7. The gas generator 4 has the function of an explosive charge and has terminals with poles “+” and “−” to which electric leads are connected, supplying electric current from a source of electric current, not shown in the figure, installed in an automotive vehicle. During an accident, a signal activating the vehicle's airbag, for example, or a different electric signal is supplied to the gas generator 4, which, after some time delay connected with stopping the vehicle movement, activates the gas generator. A mounting resilient ring 10 is installed in the chamber 3 of the opening 2 and the ring protects the gas generator 4. The chamber 3 behind the generator 4 has its face closed with a plug 12 with a cylindrical protrusion/projection 11 entering this chamber. The pressure generated by the gas generator 4 causes pressing exerted on the face of the cutting segment 7, directly or by means of the pusher 6 resulting in their shift in the opening 2 towards the working chamber 8. During this shift, the face 16 of the cylindrical cutting segment 7 moves the cutting blade 9 with a cutting edge 21 in a rectangular gap 19 of the tubular housing 1, effecting immediate cutting of the seatbelt 20 situated in a rectangular gap 18 of this tubular body 1. After cutting off the fastened seatbelt 20 the sealing ring 15 in the variety with a pusher 6 or with the sealing ring on the end of the cylindrical mandrel 7 a rests against the other (second) sealing ring 17, placed directly at the stop face 22 of the guiding chamber 1, causing total tight-sealing of the working chamber 8 with the go-through grooves 18 and 19 the same preventing undesirable penetration into them of the smoke and/or flame caused by the gas generator 4. In the second variety, without the sealing ring 17 the sealing ring 15 after cutting the belt 20, rests directly against the stop face 22. In the event of activating of the gas generator 4, the cutting segment 7 along with the cutting blade 9 will move/shift in such a manner that its face 16 will will rest against the protrusion 14 of the cover 13 which closes the working chamber 8.

In the device without the pusher 6, an elongated cutting mandrel 7 a was used, to make the length “L” of the cutting segment 7 longer than the length “L1” of the working chamber 8.

The constructional configuration described above of the automating fastened seatbelt cutting device makes it possible to cut the belts in both tensed and lax position.

The device as per the invention may be applied in means of transport furnished with seatbelts, such as: land vehicle and aircraft, working/operational machinery and other vehicles. 

1. The device for emergency cutting off fastened seatbelts in transport vehicles, especially automotive vehicles, the device having a tubular housing with an explosive charge or a gas generator installed inside, connected with a system activating the drive of belt cutting, furnished with a cutting knife and a gap for that knife or a blade and a gap for the seatbelt being cut to be placed in it, characteristic with the fact that a pusher (6) is situated between the gas generator (4) chamber (5) and the cutting segment (7), tight-sealed relative to the work chamber (8) in the guiding chamber (5), and the mass of the cylindrical cutting mandrel (7 a) of the cutting segment (7) is adjusted to the power of the gas generator (4) charge, and the cutting edge (21) of the blade (9) is one of the sides of the triangle connected with the body of the blade (9) embedded in the cutting segment (7).
 2. The device for emergency cutting off fastened seatbelts in transport vehicles, especially automotive vehicles, the device having a tubular housing with an explosive charge or a gas generator installed inside, connected with a system activating the drive of belt cutting, furnished with a cutting knife and a gap for that knife or a blade and a gap for the seatbelt being cut to be placed in it, characteristic with the fact that an extended cylindrical mandrel (7 a) is situated after the gas generator (4) chamber (5) in the cutting segment (7), and [the mandrel (7 a)] constitutes extension of this cutting segment (7) in the direction of the chamber (3), tight-sealed relative to the work chamber (8) in the guiding chamber (5), and the cutting edge (21) of the blade (9) is one of the sides of the triangle connected with the body of the blade (9) embedded in the cutting segment (7).
 3. The device for emergency cutting off fastened seatbelts, as per claim 1, characteristic with the fact that the first sealing ring (15) is placed on the pusher (6), being a separate part from the cutting segment (7) and the other sealing ring (17) is placed in the guiding chamber (5) at its stop face (22), to prevent inadvertent moving out of the cutting segment (7) towards the belt (20).
 4. The device for emergency cutting off fastened seatbelts, as per claim 2, characteristic with the fact that the first sealing ring (15) is placed on the cylindrical mandrel (7 a) of the cutting segment (7) and the other sealing ring (17) is placed in the guiding chamber (5) at its stop face (22), to prevent inadvertent moving out of the cutting segment (7) towards the belt (20) and the length (L) of the cutting segment (7) is greater than the length (L1) of the working chamber (8).
 5. The device for emergency cutting off fastened seatbelts, as per claim 2, characteristic with the fact that the sealing ring (15) is placed on the cylindrical mandrel (7 a) of the cutting segment (7) in its end part from the side of the gas generator (4) and moves along with it in the work direction of the cutting segment (7) and the length (L) of the cutting segment (7) is greater than the length (L1) of the working chamber (8).
 6. The device for emergency cutting off fastened seatbelts, as per claim 1, characteristic with the fact that the cutting edge (21) of the blade (9) is one of the sides of the triangle connected with the body of the blade (9) embedded in the cutting segment (7) and the upper vertex of this edge (21) is the point of the blade (9) situated closest towards the belt (20) to be cut off.
 7. The device for emergency cutting off fastened seatbelts, as per claim 1, characteristic with the fact that the cutting edge (21) of the blade (9) is one of the sides of the triangle connected with the body of the blade (9) embedded in the cutting segment (7) and the upper vertex of this edge (21) is the point of the blade (9) situated closest towards the gas generator (4). 